In connection with automated materials handling systems and equipment for warehouses, distribution centers, truck and airline terminals, and other industrial installations, troublesome problems arise with respect to relatively large and/or bulky articles such as mail sacks.
One particular source of trouble in such material handling systems occurs adjacent the receiving zone on the sorter conveyor through which coded articles are delivered to preselected destinations. At this location in the system, the motion of the articles must be variably controlled in accordance with various conditions both upstream and downstream along the path of travel as well as to accommodate time for entry of destination code data into a memory by personnel to control the sorter conveyor system. For proper transfer of the articles to the sorter conveyor, the massiveness of the articles, the wide variation in sizes thereof must also be dealt with.
It is, therefore, an important object of the present invention to provide apparatus for transferring hard to handle articles from the delivery end of a belt conveyor to a receiving zone on a sorter tray type conveyor in an automated materials handling system through which the articles are delivered to preselected destinations with sufficient pause in the travel of the articles to enable personnel to read coded information on the articles and enter the same into a memory. The foregoing objective is achieved with a maximum flow rate of articles and with minimum malfunction of the system by correlation of the transfer operation with upstream and downstream conditions along the path of travel.
In accordance with the present invention, the articles transferring apparatus includes one or more rotor assemblies which sequentially transports the articles to the sorter conveyor. Although adjacent rotors with article holding pockets for sequential transfer of articles are well known, they are generally operated continuously in a cyclically synchronized relationship. Contrary thereto, the rotor assemblies are controlled for intermittent operation in accordance with upstream and downstream conditions detected by photo-sensors, limit switches and malfunction sensing switches. The rotor assemblies are provided with vanes to interrupt gravitationally induced movement of the articles to sequentially effect pause in the travel of the articles, with an overlap in rotation of the rotors between indexed positions to obtain maximum flow density. The vanes on the rotors are axially elongated to accommodate articles of maximum length in a direction transverse to the direction of travel. Also, the vanes on at least one of the rotors adjacent the delivery end of the input conveyor form entrance and exit ramps in the indexed positions of the rotor to guide downward movement of the articles under gravitational inducement, movement being augmented by the vanes acting as paddles during rotation of the rotor between the indexed positions. Releasable disc brakes at opposite axial ends of the rotors hold the rotors against rotation in the indexed positions to absorb the impact of the massive articles against the vanes or paddles.
In one illustrated embodiment of the invention, a second rotor assembly adjacent the receiving zone of the sorter conveyor is provided with vanes that act as paddles instead of gates and are rotated in the same direction as the preceding rotor to handle articles such as mail bags that require additional inducement for movement onto the sorter conveyor.
The arrangement of a photo-sensing relay detecting articles on the entrance ramp vane of the rotor adjacent the input conveyor to initiate a sequential, overlapping rotational cycle of the rotors, renders the apparatus suitable for use with either a continuously operating or an intermittently operating input conveyor. Cam operated switches and additional photo-sensor actuated in response to rotation of the rotors provide input data for the sorter conveyor control system, produce the overlap in rotational movement of the rotors and correlate operation of the transfer apparatus with operating conditions of the input and sorter conveyors.